German patent number 43 13 132 issued Oct. 27, 1994 to Reinhard Baumgartner et al. discloses a particle filter in the exhaust system of a diesel engine which is cleaned by burning the soot particles adhering to the filter material and then rinsing the filter material with a liquid, which is in particular an aqueous solvent with additives. Rinsing is effected countercurrent to the exhaust stream. The aqueous solution is either delivered continuously by a pump or drawn from a liquid reservoir lying geodetically higher than the particle filter. Cleaning is effected by first completely flooding the filter material by closing the drain for the aqueous solution, then waiting until the ash has dissolved out of the filter material, and finally opening the drain and allowing the aqueous solution together with the dissolved ash to be removed from the filter material. The filter material can be dried with compressed air afterward.